The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Substrate processing systems may be used to etch film on substrates such as semiconductor wafers. The substrate processing systems typically include a processing chamber, a gas distribution device and a substrate support. During processing, the substrate is arranged on the substrate support. Different gas mixtures may be introduced into the processing chamber and radio frequency (RF) plasma may be used to activate chemical reactions.
To fabricate devices having small feature sizes such as those less than 7 nm, isotropic removal of material with nano scale control is required. Wet chemical etching causes structural damage due to pattern collapse. Dry chemical etching also causes structural damage. Atomic layer etch (ALE) provides limited isotropic removal due to ion directionality. All of these processes increase surface roughness of the underlying material that is to be etched.